oracle 学习
发布日期:2025-04-29 13:28:44 浏览次数:14 分类:精选文章

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Oracle ???????

1. ?????

??SQL Plus??Oracle?????????????

sqlplus /nolog

???????????????

conn username/password@localhost:port

???username ???????password ????localhost:port ????listen???

2. ????

  • ??????????
CREATE USER username IDENTIFIED BY password;
  • ??????????????
GRANT CONNECT TO username;GRANT RESOURCE TO username;
  • ?????????????
CREATE USER username DEFAULT TABLESPACE tablespace_name;

3. SQL ??

  • ????????
SELECT status FROM v$database;
  • ???????????
shutdown immediate;startup;

4. ????

  • ??????????
CREATE TABLE table_name (column_name column_type);ALTER TABLE table_name MOVE ONLINE TO new_tablespace;
  • ??????
CREATE TABLE new_table AS SELECT * FROM old_table;
  • ??????
TRUNCATE TABLE table_name;

5. ????

  • ???????
ALTER TABLE table_name ADD CONSTRAINT pk_column PRIMARY KEY (column_name);
  • ???????
ALTER TABLE table_name ADD CONSTRAINT ck_column CHECK (condition);
  • ???????
ALTER TABLE table_name ADD CONSTRAINT un_unique_column UNIQUE (column_name);

6. ????

  • ???????
SELECT TO_CHAR(sysdate, 'YYYY-MM-DD HH24:MI:SS') FROM DUAL;
  • ???????
ROUND(number, decimal_places);
  • ?????
TRUNC(number, decimal_places);

7. ????

  • ?????
CREATE SEQUENCE sequence_name START WITH 1 INCREMENT BY 1 MINVALUE 1 NOMAXVALUE;
  • ???????
ALTER SEQUENCE sequence_name MAXVALUE 10000;
  • ?????
DROP SEQUENCE sequence_name;

8. ?????

  • ???????????????
CREATE TABLESPACE tablespace_name DATAFILE '/u01/orcl/datafile.dbf' SIZE 100M;
  • ????????
ALTER TABLESPACE tablespace_name ADD DATAFILE '/u02/orcl/datafile2.dbf' SIZE 200M;

9. ?????

  • ???????????
RECOVER DATABASE; RECOVER DATABASE TO time_stamp;
  • ?????????
DELETE OLD SNAPSHOT LOG;

10. ????

  • ?????
SELECT * FROM dual;
  • ????????
SELECT column FROM table WHERE condition;
  • ?????
SELECT * FROM table LIMIT 10 OFFSET 5;

????????????????Oracle?????????????????????????

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